Process for the treatment of tracing



United 2,947,640 Patented Aug. 2., 1960 ice PROCESS FOR THE TREATMENT OFTRACING JAPERS TO MAKE THEM READILY ERASABLE PON Maurice J. B. Ladeuze,28 Rue Pre-Genfil, Rosny-sur-Bois, France, and Pierre Toni, 6 Villa desBuissonets, Chemin du Buisson, Champigny, France The present inventionhas for its object the provision of a process for the treatment oftracing papers permitting the very rapid erasure of lines made withChinese ink or greasy ink on the surface treated. This process has theadvantage of permitting also the erasure of all traces of pencil (bymeans of a soft rubber, known as a pencil rubber) without attacking theink lines and without altering the quality of the surface treated, onwhich the inlc lines can be rapidly erased in the dry without theemployment of a scraper by the simple rubbing of a pad of metal waddingor similar material which is very slightly abrasive; on the surface thuserased upon, new lines can be made directly without rte-finishing or resizing and the operation canbe carried out a number of times at the sameplace.

The process consists essentially in covering the surface to be treatedwith a solution, for filling the pores of the tracing paper, which ispractically colourless, and in allowing it to dry; the said coatingreduces the penetration of the ink to that necessary for a sufficientgrip in practice. Moreover, this treatment gives to the surface of thetracing paper a greater regularity, permitting toobtain lines of greaterclarity. It will be understood that this covering can be made either onfinished tracing paper, or in the last stage of manufacture, and on oneor both surfaces of the tracing paper.

The number of substances, of solvents, of piastifiers, of varnishes,which lend themselves to the composition of this filling solution isonly limited in practice by the inconveniences which certain of themwould present, either in application of the solution, its penetrationand its drying, or in the adherence of pencils and inks used later onthe surfaces treated.

The formulae indicated below are given only by way of non-limitingexample, as having given satisfactory results on various samples oftracing paper commercially available:

Formula 1 V Parts by weight (a) Alcohol (ethyl or propyl) 43 (b) Sodiumcarbonate 4 Parts by weight (c) Stearine 4 (d) Benzene 26 (e) Ethylamine9 (f) Ethanolamine 9 (g) Oleic acid Baum) 5 The products (a) (b) and (c)are heated on a water bath whilst being mixed. Then'the other productsare added. There is obtained a liquid which can be made pasty or solidby the addition of stearic acid.

Formula 2 Parts by weight (a) Alcohol (ethyl or propyl) 35 (b) Benzene35 (c) Morpholine (C H ON) 10 (d) Stearic acid Ba'um) 11 (e) Glycerine 6(f) Borax 3 The mixture constitutes a gelatinous product which can hemade more liquid or more solid. by respectively diminishing orincreasing the proportion of stearic acid.

We claim;

1. A preparation for treating tracing paper, so as to fill the poresthereof and reduce ink penetration, including the followingconstituents:

2. Tracing paper having a surface treated with the preparation claimedin claim 1.

References Cited in the fiie of this patent UNITED STATES PATENTS149,449 Dean Apr. 7, 1874 1,073,129 Horn Sept. 16, 1913 1,872,662Brathing Aug. 23, 1932 1,996,858 Davidson Apr. 9, 1935 2,005,113 SmileyJune 18, 1935 2,018,638 Driessen Oct. 22, 1935 2,205,042 Lenher et a1.June 18, 1940 2,267,240 Kummel Dec. 23, 1941 OTHER REFERENCES Witham:Modern Pulp and Paper Making (1942), 71 and 76. a

1. A PREPARATION FOR TREATING TRACING PAPER, SO AS TO FILL THE PORESTHEREOF AND REDUCE INK PENETRATION, ININCLUDING THE FOLLOWINGCONSTITUENTS: